ARS | Publication request: Estrogenicity of agricultural by-products

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 22, 2011
Publication Date: N/A

Technical Abstract: Some Minnesota farms were found to have reduced conception rates in cattle receiving embryo transfers by a local veterinarian, and dietary components were called into question. Affected farms were feeding agricultural by-products, available in either a “shredded” form or a pelletized form. These by-products are sold both within the United States and abroad, and are used as feed predominantly for cattle (both beef and dairy), but also for horses and elk. By-products were extracted to evaluate for potential estrogenic activity using the MCF-7 human mammary carcinoma cell line in the E-Screen assay. Analysis of samples submitted by the veterinarian showed estrogenicity in both unprocessed material and pellets, with the unprocessed material containing ~ three times the estrogenicity on a dry matter basis. Samples were then obtained from different regions within the Midwestern U.S., which included the unprocessed plant material, shreds and pellets. Estrogenicity was detected in all pellets examined, with a wide range of concentrations (0.1 – 2.0 ng estradiol equivalents/g dry matter) with a mean of 0.46 ng and a median of 0.28 ng estradiol equivalents per gram sample (n=9). Relative estradiol equivalents for the other sample types ranked as follows: pellets > shreds (n=3) > most unprocessed plant material (n=7). Using the recommended feeding regimen guidelines for these feedstuff cattle could consume 0.3 – 6.8 micrograms estradiol equivalence per day, however, these guidelines are often exceeded for financial reasons.